Warning about audience edit for anon users (#4883)

* Warning about audience edit for anon users

Based on https://segment.atlassian.net/browse/JON-780?atlOrigin=eyJpIjoiNjgyNmYzOGJmMzJhNDIzYTg3MTE2NGNkZjJhYmRhODIiLCJwIjoiaiJ9, eng has determined that edits to change the anon user flag are not supported by the backend, so the operation will be locked in the UI. Adding a warning note to reflect this.

* Update src/engage/audiences/index.md

---------

Co-authored-by: markzegarelli <[email protected]>

Author: estgc

src/engage/audiences/index.md

@@ -168,6 +168,8 @@ Engage then processes your realtime Audience or Trait edits. While the edit task
 > warning ""
 > It is not possible to edit an audience to convert it from real-time to batch, or vice-versa. If the computation type needs to be changed, you will need to recreate the audience with the appropriate conditions.
 
+> warning ""
+> You can't edit an audience to include anonymous users. If you need to include anonymous profiles, recreate the audience with the appropriate conditions
 
 ## Access your Audiences using the Profiles API